Contents

return {
  valid = function(isbn)
    isbn = isbn:gsub('-', '')

    if not isbn:match('^%d%d%d%d%d%d%d%d%d[%dX]$') then
      return false
    end

    local sum = 0
    for i = 1, 10 do
      sum = sum + (11 - i) * (tonumber(isbn:sub(i, i)) or 10)
    end

    return sum % 11 == 0
  end
}

Version data entries

107 entries across 107 versions & 1 rubygems

Version	Path
trackler-2.2.1.159	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.158	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.157	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.156	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.155	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.154	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.153	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.152	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.151	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.150	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.149	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.148	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.147	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.146	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.145	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.144	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.143	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.142	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.141	tracks/lua/exercises/isbn-verifier/example.lua
trackler-2.2.1.140	tracks/lua/exercises/isbn-verifier/example.lua